POLLINATION IN ORCHARDS. 



Varieties which are often self -sterile. 



constant 

 character with any variety. It is 

 influenced by the conditions under 

 '^^^ which the tree is g-rown, as are the 

 size, shape and color of the fruit. The 

 adaptation of a variety to soil and climate has 

 much to do with its self-sterility, and if a 

 tree is poorly nourished it is more likely to 

 be infertile with its own pollen. No one can 

 separate varieties of fruit into two definite 

 classes, the self-sterile and the self-fertile. 

 Thus Bartlett and Kieffer are often self- 

 sterile, but there are orchards of both which 

 are self-sterile. The same may be said of 

 many other varieties. The best that can be 

 done, therefore, is to give a list of those 

 varieties which tend to be more or less self- 

 sterile and which it would be unsafe to plant 

 alone. 



Following is a conservative list of these 

 risky varieties, drawn both from experimental 

 work and from the reports of over five 

 hundred fruit growers, who have favored me 

 with their experience. Pears : Angouleme 

 (Duchess), Bartlett, Clapp, Idaho, Kiefi'er, 

 Nelis. Apples : Bellflower, Primate, Spitzen- 

 burg-. Willow Twig, Winesap. Plums: Coes' 

 Golden Drop, French Prune, Italian Prune, 

 Kelsey, Marianna, Miner, Ogon, Peach, 

 Satsuma, Wild Goose, and according- to 

 Waugh and Kerr, all other varieties of 

 native plums except Robinson. Peach : 

 Susquehanna. Apricot : White Nicholas. 

 Cherries: Napoleon, Belle de Choisy, Reine 

 Hortense. Most of these varieties are self- 

 fertile in some places, but the weig-ht of 

 evidence shows them to be uncertain. 



It must not be inferred that all other varie- 

 ties are always able to set fruit when planted 

 alone. There are some, however, which 

 have exceptionally good records for faithful- 

 ness when planted in solid blocks, other 



conditions being favorable. Among these 

 are : Apples : Baldwin, Ben Davis, Falla- 

 water, Janet, Oldenburg, Rhode Island 

 Greening, Red Astrachan, Smith Cider. 

 Plums : Burbank, Bradshaw, DeSoto, Green 

 Gage, Lombard, Robinson and some of the 

 common blue Damsons. 



All this goes to show that the problem of 

 self-sterility is as much a study of conditions 

 as of varieties. We can set no limit ; we 

 can only indicate tendencies. 



Many large blocks of Kieffer are being 

 planted with no other varieties intermingled, 

 and it is an important point to know whether 

 this practice will give the best results. Eight 

 blocks of Kieffer in New Jersey and Dela- 

 ware have been reported as completely or 

 partially unfruitful because of self-sterility, 

 and there are also many solid blocks of 

 Kieffers in the same States which bear well. 

 Kieffer is unreliable, especially on the Dela- 

 ware peninsula. A large block of KieflFer 

 may be productive, but it does not pay to 

 take the risk, particularly since the pollen 

 of other varieties is likely to give better 

 fruit, as will be seen later on. 



Selecting the Pollinizer. 



Let us suppose that we intend to plant a 

 large block of an uncertain variety, as 

 Kieffer, because it has distinct merits as a 

 market sort. We wish to plant with it some 

 other variety to make it fruitful. There are 

 two points to be considered when selecting 

 a pollinizer for Kieffer or for any other self- 

 sterile variety ; the choice should not be in- 

 discriminate. These are simultaneous bloom- 

 ing, and mutual affinity. 



The first and most important point is that 

 the two shall blossom together, since the 

 only way in which a pollinizer can make a 

 self-sterile variety fruitful is by supplying it 



